Non-invasive molecular imaging can be performed using techniques such as single photon emission (SPE) planar imaging, single photon emission computed tomography (SPECT), positron emission tomography (PET), or Molecular Breast Imaging (MBI). Such non-invasive imaging techniques can be used for applications such as localization of cancerous lesions; guiding a surgical intervention, such as insertion of a biopsy needle or a device for surgical excision or ablation; insertion of a radioactive seed (brachytherapy), drug, stem cells or other therapeutic agent; or insertion of a guide wire or marker.
Such non-invasive imaging techniques involve the injection of a radionuclide pharmaceutical source that preferentially binds to selected tissues in the body. Radiation emitted from the source can be detected by one or more detectors. For example, Technetium Tc99m-Sestamibi (or Tc99m-Tetrofosmin) is able to bind preferentially to breast tumor cells. Tc99m-Sestamibi emits gamma radiation that can be detected by appropriate gamma radiation detectors. Cameras have been developed that employ gamma photon detectors, including solid-state cadmium zinc telluride (CZT) detectors and others.